"150 HP Dynamometer being used to measure PTO or Belt Horsepower. Photograph shows test equipment and instrumentation inside the tractor test lab. The dynamometer is labeled with a placard explaining the Horsepower calculation. A Test Lab Engineer...

"Carlton L. Zink (front) and Don Wieleage (rear), operating the dynamometer." Carlton, who was the Chief Engineer, is adjusting the electrical load and the scale in the dyno control room. Don Wielage was technician at the lab.

"Carlton Zink (Director 1930-1940) employed a number of students at the lab as assistants. This is Clee Smiley, who worked at Waterloo for J.D." He is using a Planimeter to check the trace on a chart from the Drawbar Test Dynamometer.

"Harold Mizner, a test technician, measuring drive belt pulley speed. It might be Carlton Zink at the dynamometer." On the left of the image, the rear half of an Allis-Chalmers HD-14 Diesel crawler is visible. The belt extends from the tractor...

Belt test of the Massey-Harris 22RT. Test #403, 1948. The Massey-Harris tractor is shown from the rear. The drive belt extends toward the dynamometer. An unidentified factory Rep is standing at the front of the tractor and a technician in a lab...

Dynamometer Contol panel for the large Westinghouse DC dynamometer. The image shows the dynamometer controls on the right; a scale dial (reading provides torque when it is multiplied by torque arm) On the left there are the various revolution...

Minneapolis-Moline tractor and a portion of the implement which is being field tested. The front part of the implement looks like a scarifier. The rear part apparently has some adjustment, which can be seen from the long adjustment arm on the...

The Allis-Chalmers HD-14 diesel crawler is shown from the rear inside the tractor test lab. Carlton Zink stands beside the belt pulley to measure drive pulley speed with a handheld tachometer. The driven pulley speed on the dynamometer and the...